Ohio State Department of Physics professors P. Chris Hammel, Fengyuan Yang, and Roland Kawakami are part of two research teams that have each been awarded $7.5 million Multidisciplinary University Research Initiative (MURI) grants, which will bring a total of $3.48 million to OSU.  Both awards are sponsored by the Air Force Office of Scientific Research (AFOSR).

The MURI team of professors Hammel and Yang is led by professor Enrique del Barco from the University of Central Florida and includes researchers from New York University, Oakland University, University of California at Riverside, and University of California at Santa Cruz. The team has been awarded $7.5 million for five years of funding, starting in summer 2019, under MURI’s Topic 17 on Terahertz (THz) Electronics Based on Antiferromagnets (AF). $2.24 million of that funding will be coming to OSU to support professors Hammel and Yang on the synthesis of antiferromagnetic structures and devices as well as characterization of their magnetic dynamics and spin manipulation.

Spin-electronics, or spintronics, is one of the leading candidates for next generation technologies.  Ferromagnet-based spintronics devices operate at the gigahertz (GHz) frequencies dictated by the anisotropy.  Antiferromagnets, which have been largely ignored previously for technological applications, can operate hundreds of time faster than current devices operate, that is in the THz regime governed by the interatomic exchange interaction.  In addition to the ultrahigh speed, antiferromagnetic insulator spintronics devices also require ultralow power consumption because of the extremely low damping loss.

To address this so-called “terahertz gap”, the MURI team will develop new materials and techniques, leveraging the unique properties of antiferromagnets, to transform methods of generation, transmission, and processing of THz signals.  Their project will focus on AF insulators with the goals of (1) fabrication and characterization of novel AF-based materials; (2) development of a fundamental understanding of spin-charge interconversion and THz spin dynamics; and (3) realization of magnon transport and novel applications of antiferromagnets. The objective of this MURI project is to advance the fundamental understanding of spin-charge dynamics in heterostructures based on antiferromagnetic insulators as active components with the goal of demonstrating THz-speed spin-charge manipulation for future robust, ultrahigh-speed electronics.

The MURI team of professor Kawakami is led by professor Xiaodong Xu from the University of Washington and includes researchers from Carnegie Mellon University, Cornell University, Massachusetts Institute of Technology. The research focus on developing atomically-thin, two dimensional (2D) magnetic materials and devices is funded at $7.5 million for five years under MURI Topic 19 on 2D Heterostructures for Flexible, Lightweight Electronics and Optoelectronics. Ohio State will receive $1.24 million of that funding for atomically-precise synthesis of 2D magnets and magnetic microscopies with spatial resolution down the atomic scale or with time resolution better than a picosecond (trillionth of a second).

The motivation for this research is to create new magnetic and magnetoelectronic devices with unprecedented control over their properties for improved sensors, optoelectronics, and memories that are compatible with lightweight and flexible materials platforms. This is enabled by a new class of atomically thin membranes whose magnetic, optical, and electronic properties can be tailored by epitaxial growth and stacking of heterostructures, enabling precise control over the orientation and alignment of the atomic sheets. Challenges include developing highly tunable magnetic properties, understanding how the atomic-scale structure controls the magnetic properties, demonstrating ultrafast control of magnetism, and device operation up to room temperature.